Transmission device and transmission method

ABSTRACT

In a transmission device, a signal processing circuit generates an aggregate physical layer convergence protocol data unit (A-PPDU) by adding a guard interval to each of a first part of a first physical layer convergence protocol data unit (PPDU) transmitted over each of a first through L&#39;th channel of a predetermined channel bandwidth, where L is an integer of 2 or greater, a second part of the first PPDU transmitted over each of an (L+1)&#39;th through P&#39;th channel, which is a variable channel bandwidth that is N times the predetermined channel bandwidth, where N is an integer of 2 or greater and P is an integer of L+1 or greater, and a second PPDU transmitted over the (L+1)&#39;th through P&#39;th channel. A wireless circuit transmits the A-PPDU.

BACKGROUND 1. Technical Field

The present invention relates to wireless communication, and morespecifically relates to a device and method for configuring andtransmitting aggregate physical layer convergence protocol data units(PLCP Protocol Data Units (PPDU)) in a wireless communication system.

2. Description of the Related Art

There is increasing interest in millimeter wave networks that use the 60GHz band, regarding which no license is required. Wireless Hi-Definition(HD) technology is a wireless communication standard that was the firstin the industry to use the 60 GHz band, and is capable of wirelessstreaming transmission of several gigabytes per second of at least oneof high-definition audio, video, and data, among consumer electronicdevices, personal computers, and mobile devices.

A separate wireless communication technology that operates in the 60 GHzband is WiGig technology, which has been standardized as the IEEE802.11ad standard by the Institute of Electrical and ElectronicEngineers (IEEE). WiGig technology enables implementation of physicallayer data transmission speeds up to 6.7 Gbps by using a standardchannel bandwidth of 2.16 GHz. WiGig technology supports both singlecarrier (SC) modulation and OFDM (orthogonal frequency divisionmultiplexing) modulation. Further, WiGig technology supportsAggregate-PPDU (aggregate physical layer convergence protocol dataunits, hereinafter referred to as “A-PPDU”) to improve transmissionefficiency (see IEEE 802.11ad-2012 P 237 9.13a DMG A-PPDU operation),A-PPDU is technology where two or more PPDUs are transmitted withoutproviding inter-frame spacing (IFS) or preambles therebetween.

WiGig technology can be used to substitute for cables in a wired digitalinterface. For example, WiGig technology can be used to implement awireless Universal Serial Bus (USB) link for instantaneoussynchronization in video streaming transmission to smartphones, tablets,or over an high definition multimedia interface (HDMI, a registeredtrademark) link.

The newest wired digital interfaces (e.g., USB 3.5 and HDMI 1.3) arecapable of data transmission speeds up to several tens of Gbps, andaccordingly WiGig technology is evolving to rival these. Technologywhere downwards compatibility with current WiGig (legacy WiGig)technology is maintained while supporting data transmission by variablechannel bandwidth of the standard channel bandwidth or higher is desiredfor Next Generation 60 GHz (NG60) WiGig technology, in order to achievephysical layer data transmission speeds up to several tens of Gbps.

SUMMARY

In order to maintain downwards compatibility with legacy WiGig devices,NG60 WiGig (non-legacy WiGig) devices are required to support both LF(Legacy Format) PPDUs using the standard channel bandwidth defined inIEEE 802.11ad and MF (Mixed Format) PPDUs using variable channelbandwidth. Accordingly, there is demand regarding NG60 WiGig (non-legacyWiGig) devices for definition of a format and transmission method forA-PPDUs where transmission efficiency can be maximized.

One non-limiting and exemplary embodiment provides a non-legacy A-PPDUtransmission device whereby transmission efficiency can be improved.

In one general aspect, the techniques disclosed here feature atransmission device including: a signal processing circuit thatgenerates an aggregate physical layer convergence protocol data unit(A-PPDU) by adding a guard interval to each of a first part of a firstphysical layer convergence protocol data unit (PPDU) transmitted overeach of a first through L'th channel of a predetermined channelbandwidth, where L is an integer of 2 or greater, a second part of thefirst PPDU transmitted over each of an (L+1)'th through P'th channel,which is a variable channel bandwidth that is N times the predeterminedchannel bandwidth, where N is an integer of 2 or greater and P is aninteger of L+1 or greater, and a second PPDU transmitted over the(L+1)'th through P'th channel; and a wireless circuit that transmits theA-PPDU. The first PPDU includes a legacy STF, a legacy CEF, a legacyheader field, a non-legacy STF, a non-legacy CEF, one or more non-legacyheader fields including one or more non-legacy headers, and one or moredata fields including one or more payload data. The first part of thefirst PPDU includes the legacy STF, the legacy CEF, the legacy headerfield, and the non-legacy header field. The second part of the firstPPDU includes the non-legacy STF, the non-legacy CEF, and the one ormore data fields. The second PPDU includes the one or more non-legacyheader fields and the one or more data fields. In a case where thewireless circuit transmits the first PPDU and the second PPDU by singlecarrier, each of the one or more non-legacy header fields of the secondPPDU includes a non-legacy header that has been repeated N times.

Transmission efficiency can be improved by using the non-legacy A-PPDUtransmission device and transmission method according to the presentdisclosure.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of the LF SC PPDU formataccording to conventional technology;

FIG. 2 is a diagram illustrating an example of the structure of a legacyheader of an LF SC PPDU according to conventional technology;

FIG. 3 is a diagram illustrating an example of the configuration of anLF SC PPDU transmission device according to conventional technology;

FIG. 4 is a diagram illustrating an example of the LF SC A-PPDU formataccording to conventional technology;

FIG. 5 is a diagram illustrating an example of the LF OFDM PPDU formataccording to conventional technology;

FIG. 6 is a diagram illustrating an example of the structure of a legacyheader of an LF OFDM PPDU according to conventional technology;

FIG. 7 is a diagram illustrating an example of the configuration of anLF OFDM PPDU transmission device according to conventional technology;

FIG. 8 is a diagram illustrating an example of the LF OFDM A-PPDU formataccording to conventional technology;

FIG. 9 is a diagram illustrating an example of the MF SC PPDU formattransmitting by a standard channel bandwidth according to the presentdisclosure;

FIG. 10 is a diagram illustrating an example of the structure of anon-legacy header according to the present disclosure;

FIG. 11 is a diagram illustrating an example of the MF SC PPDU formattransmitted at a variable channel bandwidth that is twice the standardchannel band width according to the present disclosure;

FIG. 12 is a diagram illustrating an example of a detailed configurationof an SC block in a data field of an MF SC PPDU according to the presentdisclosure;

FIG. 13 is a diagram illustrating an example of the MF SC A-PPDU formattransmitted at the standard channel bandwidth according to the presentdisclosure;

FIG. 14 is a diagram illustrating an example of the MF SC A-PPDU formattransmitted at a variable channel bandwidth that is twice the standardchannel band width according to the present disclosure;

FIG. 15 is a diagram illustrating an example of the MF OFDM PPDU formattransmitted at the standard channel bandwidth according to the presentdisclosure;

FIG. 16 is a diagram illustrating an example of the MF OFDM A-PPDUformat transmitted at a variable channel bandwidth that is twice thestandard channel band width according to the present disclosure;

FIG. 17 is a diagram illustrating an example of subcarrier mapping withregard to a data field of an MF OFDM PPDU according to the presentdisclosure;

FIG. 18 is a diagram illustrating an example of the MF OFDM A-PPDUformat transmitted at the standard channel bandwidth according to thepresent disclosure;

FIG. 19 is a diagram illustrating an example of the MF OFDM A-PPDUformat transmitted at a variable channel bandwidth that is twice thestandard channel band width according to the present disclosure;

FIG. 20 is a diagram illustrating an example of the MF SC A-PPDU formattransmitted at a variable channel bandwidth that is twice the standardchannel band width according to a first embodiment of the presentdisclosure;

FIG. 21 is a diagram illustrating an example of detailed configurationof an SC block in a non-legacy header field of an MF SC A-PPDU accordingto the first embodiment of the present disclosure;

FIG. 22 is a diagram illustrating an example of the configuration of anMF SC A-PPDU transmission device according to the first embodiment ofthe present disclosure;

FIG. 23 is a diagram illustrating an example of the configuration of aduplicating unit according to the first embodiment of the presentdisclosure;

FIG. 24 is a diagram illustrating an example of the MF OFDM PPDU formattransmitted at the standard channel bandwidth according to a secondembodiment of the present disclosure;

FIG. 25 is a diagram illustrating an example of the MF OFDM A-PPDUformat transmitted at a variable channel bandwidth that is twice thestandard channel band width according to the second embodiment of thepresent disclosure;

FIG. 26 is a diagram illustrating an example of subcarrier mapping withregard to a non-legacy header field of an MF OFDM PPDU according to thesecond embodiment of the present disclosure; and

FIG. 27 is a diagram illustrating an example of the configuration of anMF OFDM A-PPDU transmission device according to the second embodiment ofthe present disclosure.

FIG. 28 is a diagram illustrating an example of a method for generatingan SC block in a non-legacy header field of an MF SC A-PPDU in a casewhere a GI period has been changed, according to a third embodiment ofthe present disclosure.

DETAILED DESCRIPTION

Various embodiments of the present disclosure will be described below indetail with reference to the attached drawings. Detailed description ofknown functions and configuration included in the present specificationare omitted from the following description, for the sake of clarity andconciseness.

FIG. 1 is a diagram illustrating an example of the format of an LF SCPPDU 100 according to conventional technology. The LF SC PPDU 100includes a legacy STF 101, a legacy CEF 102, legacy header field 103 anddata field 104, an optional AGC subfield 105, and an optional TRN-R/Tsubfield 106.

The legacy STF 101 is used for packet detection, automatic gain control(AGC), frequency offset estimation, and synchronization. The legacy CEF102 is used for channel estimation. The legacy header field 103 includesa legacy header 109 that defines details of the LF SC PPDU 100. FIG. 2illustrates multiple fields included in each legacy header 109.

The data field 104 includes payload data 110 of the LF SC PPDU 100. Atleast one of audio, video, and data is included in the payload data 110.The data octet count of the data field 104 is specified by the Lengthfield of each legacy header 109, and the modulation format and the coderate used in the data field 104 are specified by the Modulation andCoding Scheme (MCS) field of the legacy header 109.

The AGC subfield 105 and TRN-R/T subfield 106 are present when the LF SCPPDU 100 is used for beam fine adjustment or tracking control. Thelength of the AGC subfield 105 and TRN-R/T subfield 106 are specified bythe Training Length field of the legacy header 109.

Whether the TRN-R/T subfield 106 is used as a TRN-R subfield, andwhether or not used as a TRN-T subfield, is specified by the Packet Typefield of the legacy header 109. All fields of the LF SC PPDU 100 aretransmitted by SC modulation using the 2.16 GHz standard channelbandwidth, as illustrated in FIG. 1.

FIG. 3 is a diagram illustrating an example of the configuration of anLF SC PPDU transmission device 300 according to the conventionaltechnology. The transmission device 300 has a baseband signal processingunit 301, a digital to analog converter (DAC) 302, a radio frequency(RF) frontend 303, and an antenna 304. Further, the baseband signalprocessing unit 301 has a scrambler 305, a low density parity check(LDPC) encoder 306, a modulator 307, a symbol blocking unit 308, and aguard interval (GI) insertion unit 309.

The scrambler 305 scrambles bits of the legacy header field 103 and datafield 104. The scrambler 305 is initialized following the ScramblerInitialization field of the legacy header 109, and starts scramblingfrom the MCS field of the legacy header 109.

The LDPC encoder 306 performs LDPC encoding of the legacy header field103 by a 3/4 code rate, and generates an LDPC codeword. The modulator307 converts the LDPC codeword into 448 complex constellation pointsusing π/2-binary phase shift keying (BPSK). The symbol blocking unit 308forms blocks of complex constellation points in increments of 448,thereby generating symbol blocks. The GI insertion unit 309 adds a GI108 made up of a Golay system 64 symbols long, that has been definedbeforehand, to the start of the symbol block, thereby generating an SCblock.

The LDPC encoder 306 performs LDPC encoding of the payload data 110 inthe data field 104, at the code rate specified in the MCS field in thelegacy header, thereby generating an LDPC codeword. The modulator 307coverts the LDPC codeword into multiple complex constellation pointsusing the modulation format specified in the MCS field in the legacyheader. The symbol blocking unit 308 forms blocks of complexconstellation points in increments of 448, thereby generating symbolblocks.

The GI insertion unit 309 adds the same GI 108 as the legacy headerfield 103 to the start of each symbol block, thereby generating the SCblock 107. Further, in order to facilitate frequency regionequalization, the GI insertion unit 309 adds a GI 108 a to the end ofthe final SC block 107 of the data field 104. That is to say, in a casewhere the Additional PPDU field of the legacy header is not 1, the GI108 a is added.

The DAC 302 converts digital baseband signals, including the LF SC PPDU100 generated at the baseband signal processing unit 301, into analogbaseband signals. The RF frontend 303 converts analog baseband signalsincluding the LF SC PPDU 100 into radio frequency signals by frequencyconversion, amplifying, and other such processing. The antenna 304 emitsthe wireless frequency signals into space.

FIG. 4 is a diagram illustrating an example of the format of an LF SCA-PPDU 400 according to conventional technology. The LF SC A-PPDU 400 ismade up of three LF SC PPDUs 401, 402, and 403. The LF SC PPDUs arelinked without an IFS or preamble therebetween, and include legacyheader fields 406, 408, and 410, and data fields 407, 409, and 411.

For example, the LF SC PPDU 401 disposed at the start of the LF SCA-PPDU 400 includes the legacy header field 406, data field 407, legacySTF 404, and legacy CEF 405. The LF SC PPDU 403 disposed at the end ofthe LF SC A-PPDU 400 includes the legacy header field 410, data field411, optional AGC subfield 412 and optional TRN-R/T subfield 413.

Definitions of the legacy STF 404, legacy CEF 405, legacy header fields406, 408, and 410, AGC subfield 412, and TRN-R/T subfield 413 are thesame as the definitions of the corresponding fields of the LF SC PPDU100 in FIG. 1, so description will be omitted.

With the exception of the LF SC PPDU 403, the LF SC PPDU 401 for exampleis followed by a different LF SC PPDU 402, so the Additional PPDU fieldof the legacy header field 410 of the LF SC PPDU 403 is set to 0, whilethe Additional PPDU fields of the legacy header fields 406 and 408 ofthe other LF SC PPDUs 401 and 402 are set to 1.

For example, with the exception of the data field 411 of the LF SC PPDU403, the final SC block 414 of the data field 407 is followed by the SCblock 415 at the start of the legacy header field 408 of a different LFSC PPDU 402, so addition of a GI 417 a is omitted, but the end of thefinal SC block 416 of the data field 411 of the LF SC PPDU 403 isfollowed by no SC block, so a GI 417 a is added. That is to say, in acase where the Additional PPDU field of a legacy header is 1, additionof the GI 417 a is omitted. Note that all fields of the LF SC A-PPDU 400are transmitted by SC modulation using the 2.16 GHz standard channelbandwidth.

FIG. 5 is a diagram illustrating an example of the format of an LF OFDMPPDU 500 according to conventional technology. The LF OFDM PPDU 500includes a legacy STF 501, a legacy CEF 502, legacy header field 503, adata field 504, an optional AGC subfield 505, and an optional TRN-R/Tsubfield 506. Definitions of the legacy STF 501, legacy CEF 502, AGCsubfield 505, and TRN-R/T subfield 506 are the same as the definitionsof the corresponding fields of the LF SC PPDU 100 in FIG. 1, sodescription will be omitted,

The legacy header field 503 includes a legacy header 510 definingdetails of the LF OFDM PPDU 500. FIG. 6 illustrates multiple fieldsincluded in the legacy header 510. The data field 504 includes payloaddata 511 of the LF OFDM PPDU 500, Note that all fields of the LF OFDMPPDU 500 are transmitted using the 2.16 GHz standard channel bandwidth.The legacy STF 501, legacy CEF 502, AGC subfield 505, and TRN-R/Tsubfield 506 are transmitted by SC modulation, while the legacy headerfield 503 and data field 504 are transmitted by OFDM modulation.

The legacy header field 503 and data field 504 transmitted by OFDMmodulation are transmitted at a faster sampling rate than the legacy STF501, legacy CEF 502, AGC subfield 505, and TRN-R/T subfield transmittedby SC modulation. Accordingly, sampling rate conversion processing isnecessary at the boundary between the legacy CEF 502 and the legacyheader field 503, and the boundary between the data field 504 and AGCsubfield 505.

FIG. 7 is a diagram illustrating an example of the configuration of anLF OFDM PPDU transmission device 700 according to conventionaltechnology. The transmission device 700 has a baseband signal processingunit 701, a DAC 702, an RF frontend 703, and an antenna 704. Thebaseband signal processing unit 701 further includes a scrambler 705, anLDPC encoder 706, a modulator 707, a subcarrier mapping unit 708, anIFFT unit 709, and a GI insertion unit 710.

The scrambler 705 scrambles bits of the legacy header field 503 and datafield 504. The scrambler 705 is initialized following the ScramblerInitialization field of the legacy header, and starts scrambling fromthe MCS field of the legacy header.

The LDPC encoder 706 performs LDPC encoding of the legacy header 510 bya 3/4 code rate, and generates an LDPC codeword. The modulator 707converts the LDPC codeword into 336 complex constellation points usingquadrature phase shift keying (QSPK). The subcarrier mapping unit 708maps the 336 complex constellation points as to 336 data subcarriersfollowing rules defined beforehand.

There are a total of 512 subcarriers, with the remaining 176 subcarriersbeing used as DC subcarrier, pilot subcarrier, and guard band. The IFFTunit 709 converts the legacy header 510 subcarrier-mapped in frequencyregion, to time region signals by IFFT processing at 512 points. The GIinsertion unit 710 copies the trailing 128 samples of the output signalsfrom the IFFT unit 709 and connects these to the start of the IFFToutput signals as a GI 507, thereby generating OFDM symbols. Note that aGI may be referred to as a cyclic prefix (CP) with regard to OFDMsymbols.

The LDPC encoder 706 performs LDPC encoding of the payload data 511, atthe code rate specified in the MCS field in the legacy header 510,thereby generating an LDPC codeword. The modulator 707 coverts the LDPCcodeword into multiple complex constellation points using the modulationformat specified in the MCS field in the legacy header 510.

The subcarrier mapping unit 708 maps the 336 complex constellationpoints as to 336 data subcarriers following rules defined beforehand.There are a total of 512 subcarriers, with the remaining 176 subcarriersbeing used as DC subcarrier, pilot subcarrier, and guard band.

The IFFT unit 709 converts the payload data 511 subcarrier-mapped infrequency region, to time region signals by IFFT processing at 512points. The GI insertion unit 710 copies the trailing 128 samples of theoutput signals from the IFFT unit 709 and connects these to the start ofthe IFFT output signals as a GIs 508 and 509, thereby generating OFDMsymbols.

The DAC 702 converts digital baseband signals, including the LF OFDMPPDU 100 generated at the baseband signal processing unit 701, intoanalog baseband signals. The RF frontend 703 converts analog basebandsignals including the LF OFDM PPDU 100 into radio frequency signals byfrequency conversion, amplifying, and other such processing. The antenna704 emits the wireless frequency signals into space.

FIG. 8 is a diagram illustrating an example of the format of an LF OFDMA-PPDU 800 according to conventional technology. The LF OFDM A-PPDU 800is made up of three LF OFDM PPDUs 801 802, and 803. The LF OFDM PPDUsare linked without an IFS or preamble therebetween, and include legacyheader fields 806, 808, and 810, and data fields 807, 809, and 811.

The LF OFDM PPDU 801 disposed at the start of the LF OFDM A-PPDU 800includes the legacy header field 806, data field 807, legacy STF 804,and legacy CEF 805. The LF OFDM PPDU 803 disposed at the end of the LFOFDM A-PPDU 800 includes the legacy header field 810, data field 811,optional AGC subfield 812, and optional TRN-R/T subfield 813.Definitions of the legacy STF 804, legacy CEF 805, legacy header fields806, 808, and 810, data fields 807, 809, and 811, AGC subfield 812, andTRN-R/T subfield 813 are the same as the definitions of thecorresponding fields of the LF OFDM PPDU 500 in FIG. 5, so descriptionwill be omitted.

In FIG. 8, the LF OFDM PPDUs 801 and 802 are followed by different LFOFDM PPDUs 802 and 803, so the Additional PPDU fields of the legacyheader fields 806 and 808 of the LF OFDM PPDU 801 and 802 are set to 1,while the Additional PPDU field of the legacy header field 810 of the LFOFDM PPDU 803 that has no following LF OFDM PPDU is set to 0.

In FIG. 8, all fields of the LF OFDM A-PPDU 800 are transmitted usingthe 2.16 GHz standard channel bandwidth. The legacy STF 804, legacy CEF805, AGC subfield 812, and TRN-R/T subfield 813 of the LF OFDM A-PPDU800 are transmitted by SC modulation, while the legacy headers 806, 808,810 and data fields 807, 809, and 811 are transmitted by OFDMmodulation. Note that in FIG. 8, the payload data 814 at the last stageof each LF OFDM PPDU does not have to be followed by a GI 815.

FIG. 9 is a diagram illustrating an example of the format of an MF SCPPDU 900 transmitted at standard channel bandwidth according to thepresent disclosure. The MF SC PPDU 900 includes a legacy STF 901, alegacy CEF 902, a legacy header field 903, a non-legacy header field904, a non-legacy STF 905, a non-legacy CEF 906, a data field 907, anoptional AGC subfield 908, and an optional TRN-R/T subfield 909.

Note however, that the non-legacy STF 905 and non-legacy CEF 906 may beomitted in a case where the data field 907 is transmitted using singleinput single output (SISO), since the AGC level adjusted at the legacySTF 901 and the channel estimation results obtained at the legacy CEF902 can be used for the data field 907. Definitions of the legacy STF901, legacy CEF 902, legacy header field 903, AGC subfield 908, andTRN-R/T subfield 909 are the same as the definitions of thecorresponding fields of the LF SC PPDU 100 in FIG. 1, so descriptionwill be omitted.

The non-legacy header field 904 includes a non-legacy header 913 thatdefines details of the MF SC PPDU 900. FIG. 10 illustrates multiplefields included in a non-legacy header.

In a case where the non-legacy STF 905 or the non-legacy CEF 906 ispresent in the MF SC PPDU 900, a GI 912 is added to the end of the lastSC block 910 of the non-legacy header field 904, in order to facilitatefrequency region equalization.

The non-legacy STF 905 is used for AGC readjustment. The non-legacy CEF906 is used for channel estimation for the data field 907.

The data field 907 includes payload data 914 of the MF SC PPDU 900. Thedata octet count of the data field 907 is specified by the PSDU Lengthfield of each non-legacy header, and the modulation format and the coderate used in the data field 907 are specified by the non-legacy MCSfield of the non-legacy header. A GI 912 a is added to the end of thelast SC block 911 of the data field 907, in order to facilitatefrequency region equalization. Note that all fields of the MF SC PPDU900 are transmitted by SC modulation using the 2.16 GHz standard channelbandwidth.

FIG. 11 is a diagram illustrating an example of the format of an MF SCPPDU 1100 transmitted at a variable channel bandwidth that is double thestandard channel bandwidth according to the present disclosure. The MFSC PPDU 1100 includes a legacy STF 1101, a legacy CEF 1102, a legacyheader field 1103, a non-legacy header field 1104, a non-legacy STF1105, a non-legacy CEF 1106, a data field 1107, an optional AGC subfield1108, and an optional TRN-R/T subfield 1109. Definitions of the legacySTF 1101, legacy CEF 1102, legacy header field 1103, non-legacy headerfield 1104, optional AGC subfield 1108, and optional TRN-R/T subfield1109 are the same as the definitions of the corresponding fields of theMF SC PPDU 900 in FIG. 9, so description will be omitted.

The channel bandwidth differs among the data field 1107, legacy STF1101, and legacy CEF 1106, so the non-legacy STF 1105 and non-legacy CEF1106 are present in the MF SC PPDU 1100. Accordingly, a GI 1111 usingthe 2.16 GHz standard channel bandwidth is added to the end of the finalSC block 1110 of the non-legacy header field 1104.

In FIG. 11, the legacy STF 1101, legacy CEF 1102, legacy header field1103, and non-legacy header field 1104 are duplicated, and transmittedby the standard channel bandwidth B (i.e., 2.16 GHz), each with afrequency offset B/2 that is half band of the standard channel bandwidthB (i.e., 1.08 GHz).

On the other hand, the non-legacy STF 1105, non-legacy CEF 1106, datafield 1107, AGC subfield 1108, and TRN-R/T subfield 1109 are transmittedat the variable channel bandwidth 2 B that is a band double the standardchannel bandwidth B (i.e., 4.32 GHz). Accordingly, sampling rateconversion processing is performed at the boundary between thenon-legacy header field 1104 and non-legacy STF 1105. Note that allfields of the MF SC PPDU 1100 are transmitted by SC modulation. Althoughthe illustration in FIG. 11 takes into consideration the bandwidth thateach field occupies, illustration in subsequent diagrams will be madeusing channel bandwidth, for the sake of simplifying the drawings.

FIG. 12 is a diagram illustrating an example of a detailed configurationof an SC block in a data field of an MF SC PPDU according to the presentdisclosure. Illustrated are a symbol count N_(GI) of a GI when using thestandard channel bandwidth, a symbol count N_(D) of payload data per SCblock when using the standard channel bandwidth, GI period T_(GI), dataperiod T_(D) of payload data, and ratio of standard channel bandwidthand variable channel bandwidth (i.e., variable channelbandwidth/standard channel bandwidth) R_(CB). Accordingly, R_(CB)=1indicates the SC block configuration of the data field 907 in FIG. 9,while R_(CB)=2 indicates the SC block configuration of the data field1107 in FIG. 11.

It is demanded of symbol blocking and GI insertion to maintaininterference avoidance capabilities regarding multipath delay waves andtransmission efficiency, which is to say to maintain the GI period toT_(GI) regardless of the R_(CB), and keep the ratio between the GIperiod T_(GI) and the data period T_(D) constant. The GI and payloaddata symbol length is short in proportion to R_(CB), so the GI period ismaintained at T_(GI) by setting the GI size to R_(CB)×N_(GI). Also, thedata period is maintained at T_(D) by setting the data size toR_(CB)×N_(D). The ratio between the GI period and the data period iskept constant by the above settings. Note that the SC blockconfiguration in the non-legacy header field transmitted at the standardchannel bandwidth is the same as the case where R_(CB)=1.

FIG. 13 is a diagram illustrating an example of the format of an MF SCA-PPDU 1300 transmitted at the standard channel bandwidth, according tothe present disclosure. The MF SC A-PPDU 1300 includes three MF SC PPDUs1301, 1302, and 1303. The MF SC PPDUs are linked without an IFS orpreamble therebetween, and include non-legacy header fields and datafields.

For example, the MF SC PPDU 1301 disposed at the start of the MF SCA-PPDU 1300 includes a non-legacy header field 1307, data field 1310,legacy STF 1304, legacy CEF 1305, legacy header field 1306, non-legacySTF 1308, and non-legacy CEF 1309.

Note however, that in a case where the data fields 1310, 1312, and 1314are transmitted using SISO, the non-legacy STF 1308 and non-legacy CEF1309 may be omitted, since the AGC level adjusted at the legacy STF 1304and channel estimation results obtained at the legacy CEF 1305 can beused in the data fields 1310, 1312, and 1314.

Note that the MF SC PPDU 1303 at the end of the MF SC A-PPDU 1300includes a non-legacy header field 1313, a data field 1314, an optionalAGC subfield 1315, and an optional TRN-R/T subfield 1316. Definitions ofthe legacy STF 1304, legacy CEF 1305, legacy header field 1306,non-legacy header fields 1307, 1311, and 1313, non-legacy STF 1308,non-legacy CEF 1309, AGC subfield 1315, and TRN-R/T subfield 1316 arethe same as the definitions of the corresponding fields of the MF SCPPDU 900 in FIG. 9, so description will be omitted.

The MF SC PPDU 1303 is not followed by another MF SC PPDU, so theAdditional PPDU field of the non-legacy header field 1313 of the MF SCPPDU 1303 is set to 0, while the MF SC PPDUs 1301 and 1302 are followedby other MF SC PPDUs 1302 and 1303, so the Additional PPDU field of thenon-legacy header fields (1307 and 1311) are set to 1. Note that theAdditional PPDU field in the legacy header field 1306 is set to 0, sothat the MF SC A-PPDU 1300 will be received as a conventional LF SC PPDUby a legacy device.

With the exception of the data field 1314 of the MF SC PPDU 1303, forexample, the final SC block 1317 of the data field 1310 is followed bythe SC block 1318 at the start of the non-legacy header field 1311 ofthe following MF SC PPDU 1302, so addition of a GI 1320 a is omitted,but the final SC block 1319 of the data field 1314 of the MF SC PPDU1303, regarding which there is no following MF SC PPDU, is followed byno SC block, so a GI 1320 a is added to the end. That is to say, in acase where the Additional PPDU field of a legacy header is 1, additionof the GI 1320 a is omitted. Note that all fields of the MF SC A-PPDU1300 are transmitted by SC modulation using the 2.16 GHz standardchannel bandwidth.

FIG. 14 is a diagram illustrating an example of the format of an MF SCA-PPDU 1400 transmitted at the variable channel bandwidth that is a banddouble the standard channel bandwidth. The MF SC A-PPDU 1400 is made upof three MF SC PPDUs 1401, 1402, and 1403. The MF SC PPDUs are linkedwithout an IFS or preamble therebetween, and include non-legacy headerfields and data fields.

For example, the MF SC PPDU 1401 disposed at the start of the MF SCA-PPDU 1400 includes a non-legacy header field 1407, data field 1410,legacy STF 1404, legacy CEF 1405, legacy header field 1406, non-legacySTF 1408, and non-legacy CEF 1409.

Note that the MF SC PPDU 1403 disposed at the end of the MF SC A-PPDU1400 includes a non-legacy header field 1407, a data field 1410, anoptional AGC subfield 1415, and an optional TRN-R/T subfield 1416.Definitions of the legacy STF 1404, legacy CEF 1405, legacy header field1406, non-legacy header fields (1407, 1411, and 1413), non-legacy STF1408, non-legacy CEF 1409, AGC subfield 1415, and TRN-R/T subfield 1416are the same as the definitions of the corresponding fields of the MF SCPPDU 1100 in FIG. 11, so description will be omitted.

The MF SC PPDU 1403 is not followed by another MF SC PPDU, for example,so the Additional PPDU field of the non-legacy header field 1413 is setto 0, while the MF SC PPDUs 1401 and 1402 are followed by another MF SCPPDU, so the Additional PPDU field of the non-legacy header fields 1407and 1411 are set to 1. Note that the Additional PPDU field of the legacyheader in the legacy header field 1406 is set to 0, so that the MF SCA-PPDU 1400 will be received as a conventional LF SC PPDU by a legacydevice.

The data fields 1410, 1412, and 1414 are transmitted by a broaderchannel bandwidth than the non-legacy header fields 1407, 1411, and1413, so a GI 1420 a is added to the end of the final SC blocks 1418 and1422 of the non-legacy header fields 1411 and 1413 in the MF SC PPDUs1402 and 1403, even in a case where data fields 1412 and 1414immediately follow the non-legacy header fields 1411 and 1413.

The MF SC PPDU 1403 is not followed by another MF SC PPDU, so a GI 1421a is added to the end of the final SC block 1419 of the data field 1414.On the other hand, the MF SC PPDUs 1401 and 1402 are followed by otherMF SC PPDUs 1402 and 1403, but the channel bandwidth differs between thedata fields 1410 and 1412 and the subsequent non-legacy header fields1411 and 1413, so a GI 1421 a is added to the end of the final SC block1417 and 1423 of the data fields 1410 and 1412, in the same way as withthe MF SC PPDU 1403. Also, sampling rate conversion processing isperformed at the boundaries between the data fields 1410 and 1412, andthe subsequent non-legacy header fields 1411 and 1413.

In FIG. 14, the legacy STF 1404, legacy CEF 1405, legacy header field1406, and non-legacy header field 1407 are duplicated, and transmittedby the standard channel bandwidth B (i.e., 2.16 GHz), each with afrequency offset B/2 that is half band of the standard channel bandwidthB (i.e., 1.08 GHz). On the other hand, the non-legacy STF 1408,non-legacy CEF 1409, data fields 1410, 1412, and 1414, AGC subfield1415, and TRN-R/T subfield 1416 are transmitted at the variable channelbandwidth 2 B that is a band double the standard channel bandwidth B(i.e., 4.32 GHz). Note that all fields of the MF SC A-PPDU 1400 aretransmitted by SC modulation.

FIG. 15 is a diagram illustrating an example of the format of an MF OFDMPPDU 1500 transmitted at the standard channel bandwidth according to thepresent disclosure. The MF OFDM PPDU 1500 includes a legacy STF 1501, alegacy CEF 1502, a legacy header field 1503, a non-legacy header field1504, a non-legacy STF 1505, a non-legacy CEF 1506, a data field 1507,an optional AGC subfield 1508, and an optional TRN-R/T 1509. Note thatin a case where the data field 1507 is transmitted using SISO, thenon-legacy STF 1505 and non-legacy CEF 1506 may be omitted, since theAGC level adjusted at the legacy STF 1501 and channel estimation resultsobtained at the legacy CEF 1502 can be used in the data field 1507.

Definitions of the legacy STF 1501 legacy CEF 1502, legacy header field1503, AGC subfield 1508, and TRN-R/T subfield 1509 are the same as thedefinitions of the corresponding fields of the LF OFDM PPDU 500 in FIG.5, so description will be omitted. The configuration of the non-legacyheader included in the non-legacy header field 1504 is the same as thatin FIG. 10.

All fields of the MF OFDM PPDU 1500 in FIG. 15 are transmitted using the2.16 GHz standard channel bandwidth. The legacy STF 1501, legacy CEF1502, legacy header field 1503, non-legacy header field 1504, non-legacySTF 1505, AGC subfield 1508, and TRN-R/T subfield 1509 are transmittedby SC modulation, while the non-legacy CEF 1506 and data field 1507 aretransmitted by OFDM modulation. Accordingly, a GI 1511 a is added to theend of the final SC block 1510 of the non-legacy header field 1504 evenin a case where the non-legacy STF 1505 and non-legacy CEF 1506 are notpresent.

The non-legacy CEF 1506 and data field 1507 that are transmitted by OFDMmodulation are transmitted at a faster sampling rate than the legacy STF1501, legacy CEF 1502, legacy header field 1503, non-legacy header field1504, non-legacy STF 1505, AGC subfield 1508, and TRN-R/T subfield 1509,which are transmitted by SC modulation, in the same way as with the LFOFDM PPDU 500 in FIG. 5. Accordingly, sampling rate conversionprocessing is implemented at the boundary between the non-legacy STF1505 and the non-legacy CEF 1506, and the boundary between the datafield 1507 and AGC subfield 1508.

FIG. 16 is a diagram illustrating an example of the format of an MF OFDMPPDU 1600 transmitted at a variable channel bandwidth that is double thestandard channel bandwidth B according to the present disclosure. The MFOFDM PPDU 1600 includes a legacy STF 1601, a legacy CEF 1602, a legacyheader field 1603, a non-legacy header field 1604, a non-legacy STF1605, a non-legacy CEF 1606, a data field 1607, an optional AGC subfield1608, and an optional TRN-R/T 1609. Definitions of the legacy STF 1601,legacy CEF 1602, legacy header field 1603, non-legacy header field 1604,AGC subfield 1608, and TRN-R/T subfield 1609 are the same as thedefinitions of the corresponding fields of the MF OFDM PPDU 1500 in FIG.15, so description will be omitted.

The channel bandwidth differs among the data field 1607, legacy STF1601, and legacy CEF 1602, so the non-legacy STF 1605 and non-legacy CEF1606 are present in the MF OFDM PPDU 1600. Accordingly, a GI 1611 a isadded to the end of the final SC block 1610 of the non-legacy headerfield 1604.

In FIG. 16, the legacy STF 1601, legacy CEF 1602, legacy header field1603, and non-legacy header field 1604 are duplicated, and transmittedby the standard channel bandwidth B (i.e., 2.16 GHz), each with afrequency offset B/2 that is half band of the standard channel bandwidthB (i.e., 1.08 GHz). On the other hand, the non-legacy STF 1605,non-legacy CEF 1606, data field 1607, AGC subfield 1608, and TRN-R/Tsubfield 1609 are transmitted at the variable channel bandwidth 2 B thatis a band double the standard channel bandwidth B (i.e., 4.32 GHz).Accordingly, sampling rate conversion processing is performed at theboundary between the non-legacy header field 1604 and non-legacy STF1605.

Also, the legacy STF 1601, legacy CEF 1602, legacy header field 1603,non-legacy header field 1604, non-legacy STF 1605, AGC subfield 1608,and TRN-R/T 1609 are transmitted by SC modulation, while the non-legacyCEF 1606 and data field 1607 are transmitted by OFDM modulation.Accordingly, sampling rate conversion processing is performed at theboundary between the non-legacy STF 1605 and non-legacy CEF 1606, and atthe boundary between the data field 1607 and AGC subfield 1608.

FIG. 17 is a diagram illustrating an example of subcarrier mapping inthe data fields 1507 and 1607 of the MF OFDM PPDU 1500 and 1600according to the present disclosure. Illustrated in FIG. 17 are a datasubcarrier count N_(SD) (payload data symbol count) when the standardchannel bandwidth B is used, and ratio of standard channel bandwidth andvariable channel bandwidth (i.e., variable channel bandwidth I standardchannel bandwidth) R_(CB).

Although data subcarriers are illustrated in FIG. 17 for the sake ofsimplicity, DC subcarrier, pilot subcarrier, and guard band are alsopresent in an actual MF OFDM PPDU. In FIG. 17, the data subcarrier countincreases proportionately to R_(CB) in the MF OFDM PPDU, so the symbolcount of payload data to be mapped to data subcarriers also increasesproportionately to R_(CB).

FIG. 18 is a diagram illustrating an example of the format of an MF OFDMA-PPDU 1800 transmitted at the standard channel bandwidth according tothe present disclosure. The MF OFDM A-PPDU 1800 is made up of three MFOFDM PPDUs 1801, 1802, and 1803. The MF OFDM PPDUs are linked without anIFS or preamble therebetween, and include non-legacy header fields anddata fields.

For example, the MF OFDM PPDU 1801 disposed at the start of the MF OFDMA-PPDU 1800 includes a non-legacy header field 1807, data field 1810,legacy STF 1804, legacy CEF 1805, legacy header field 1806, non-legacySTF 1808, and non-legacy CEF 1809. Note that in a case where the datafields 1810, 1812, and 1814 are transmitted using SISO, the non-legacySTF 1808 and non-legacy CEF 1809 may be omitted, since the AGC leveladjusted at the legacy STF 1804 and channel estimation results obtainedat the legacy CEF 1805 can be used in the data fields 1810, 1812, and1814.

The MF OFDM PPDU 1803 disposed at the end of the MF OFDM A-PPDU 1800includes a non-legacy header field 1807, a data field 1810, an optionalAGC subfield 1815, and an optional TRN-R/T 1816. Definitions of thelegacy STF 1804, legacy CEF 1805, legacy header field 1806, non-legacyheader fields 1807, 1811, and 1813, non-legacy STF 1808, non-legacy CEF1809, AGC subfield 1815, and TRN-R/T subfield 1816 of the MF OFDM A-PPDU1800 are the same as the definitions of the corresponding fields of theMF OFDM PPDU 1500 in FIG. 15, so description will be omitted.

The MF OFDM PPDU 1803 is not followed by another MF OFDM PPDU, so theAdditional PPDU field of the non-legacy header field 1813 of the MF OFDMPPDU 1803 is set to 0, while the MF SC PPDUs 1801 and 1802 are followedby another MF OFDM PPDU, so the Additional PPDU field of the non-legacyheader fields 1807 and 1811 are set to 1. Note that the Additional PPDUfield in the legacy header included in the legacy header field 1806 isset to 0, so that the MF OFDM A-PPDU 1800 will be received as aconventional LF OFDM PPDU by a legacy device.

In FIG. 18, all fields of the MF OFDM A-PPDU 1800 are transmitted usingthe 2.16 GHz standard channel bandwidth. Also, the legacy STF 1804,legacy CEF 1805, legacy header field 1806, non-legacy header fields1807, 1811, and 1813, non-legacy STF 1808, AGC subfield 1815, andTRN-R/T subfield 1816 are transmitted by SC modulation, while thenon-legacy CEF 1809 and data fields 1810, 1812, and 1814 are transmittedby OFDM modulation.

Accordingly, sampling rate conversion processing is performed at theboundary between the data field 1810 and the non-legacy header field1811, at the boundary between the non-legacy header field 1811 and thedata field 1812, at the boundary between the data field 1812 and thenon-legacy header field 1813, and at the boundary between the non-legacyheader field 1813 and the data field 1814.

FIG. 19 is a diagram illustrating an example of the format of an MF OFDMA-PPDU 1900 transmitted at the variable channel bandwidth that is doublethe standard channel bandwidth B, according to the present disclosure.

The MF OFDM A-PPDU 1900 is made up of three MF OFDM PPDUs 1901, 1902,and 1903. The MF OFDM PPDUs are linked without an IFS or preambletherebetween, and include non-legacy header fields and data fields, Forexample, the MF OFDM PPDU 1901 disposed at the start of the MF OFDMA-PPDU 1900 includes a non-legacy header field 1907, data field 1910,legacy STF 1904, legacy CEF 1905, legacy header field 1906, non-legacySTF 1908, and non-legacy CEF 1909.

The MF OFDM PPDU 1903 disposed at the end of the MF OFDM A-PPDU 1900includes a non-legacy header field 1913, a data field 1914, an optionalAGC subfield 1915, and an optional TRN-R/T 1916. Definitions of thelegacy STF 1904, legacy CEF 1905, legacy header field 1906, non-legacyheader fields 1907, 1911, and 1913, non-legacy STF 1908, non-legacy CEF1909, AGC subfield 1915, and TRN-R/T subfield 1916 are the same as thedefinitions of the corresponding fields of the MF OFDM PPDU 1600 in FIG.16, so description will be omitted.

The MF OFDM PPDU 1903 is not followed by another MF OFDM PPDU, so theAdditional PPDU field of the non-legacy header field 1913 of the MF OFDMPPDU 1903 is set to 0, while the MF OFDM PPDUs 1901 and 1902 arefollowed by other MF OFDM PPDUs 1902 and 1903, so the Additional PPDUfield of the non-legacy header fields 1907 and 1911 are set to 1. Notethat the Additional PPDU field of the legacy header included in thelegacy header field 1906 is set to 0, so that the MF OFDM A-PPDU 1900will be received as a conventional LF OFDM PPDU by a legacy device.

In FIG. 19, the legacy STF 1904, legacy CEF 1905, legacy header field1906, and non-legacy header fields 1907, 1911, and 1913 are duplicated,and transmitted by the standard channel bandwidth B (i.e., 2.16 GHz),each with a frequency offset B/2 that is half band of the standardchannel bandwidth B (i.e., 1.08 GHz). On the other hand, the non-legacySTF 1908, non-legacy CEF 1909, data fields 1910, 1912, and 1914, AGCsubfield 1915, and TRN-R/T subfield 1916 are transmitted at the variablechannel bandwidth 2 B that is a band double the standard channelbandwidth B (i.e., 4.32 GHz).

Also, the legacy STF 1904, legacy CEF 1905, legacy header field 1906,non-legacy header fields 1907, 1911, and 1913, non-legacy STF 1908, AGCsubfield 1915, and TRN-R/T subfield 1916 are transmitted by SCmodulation, while the non-legacy CEF 1909 and data fields 1910, 1912,and 1914 are transmitted by OFDM modulation.

Accordingly, sampling rate conversion processing is performed at theboundary between the data field 1910 and the non-legacy header field1911, at the boundary between the non-legacy header field 1911 and thedata field 1912, at the boundary between the data field 1912 and thenon-legacy header field 1913, and at the boundary between the non-legacyheader field 1913 and the data field 1914.

First Embodiment

FIG. 20 is a diagram illustrating an example of the format of an MF SCA-PPDU 2000 transmitted at the variable channel bandwidth that is doublethe standard channel bandwidth, according to a first embodiment of thepresent disclosure. The MF SC A-PPDU 2000 is made up of three MF SCPPDUs 2001, 2002, and 2003. The MF SC PPDUs are linked without an IFS orpreamble therebetween, and include non-legacy header fields and datafields. The data fields include at least one of audio, video, and data.

For example, the MF SC PPDU 2001 disposed at the start of the MF SCA-PPDU 2000 includes a non-legacy header field 2007, data field 2010,legacy STF 2004, legacy CEF 2005, legacy header field 2006, non-legacySTF 2008, and non-legacy CEF 2009. The MF SC PPDU 2003 disposed at theend of the MF SC A-PPDU 2000 includes a non-legacy header field 2013, adata field 2014, an optional AGC subfield 2015, and an optional TRN-R/Tsubfield 2016. Definitions of the legacy STF 2004, legacy CEF 2005,legacy header field 2006, non-legacy STF 2008, non-legacy CEF 2009, AGCsubfield 2015, and TRN-R/T subfield 2016 are the same as the definitionsof the corresponding fields of the MF SC A-PPDU 1400 in FIG. 14, sodescription will be omitted.

The difference between the MF SC A-PPDU 1400 in FIG. 14 and the MF SCA-PPDU 2000 in FIG. 20 will be described below. In FIG. 20, thenon-legacy header field of the MF SC PPDU 2001 disposed at the start istransmitted by the standard channel bandwidth B, and the non-legacyheader fields 2011 and 2013 of the MF SC PPDUs 2002 and 2003 disposed atthe second sequential order and thereafter are transmitted by thevariable channel bandwidth 2 B.

That is to say, in FIG. 20 the non-legacy header field 2007 isduplicated, and each is transmitted by the standard channel bandwidth B(i.e., 2.16 GHz), each with a frequency offset B/2 that is half band ofthe standard channel bandwidth B (i.e., 1.08 GHz), but the non-legacyheader fields 2011 and 2013 are transmitted at the variable channelbandwidth 2 B that is a band double the standard channel bandwidth B(i.e., 4.32 GHz). Accordingly, a GI 2022 a is added to the end of thefinal SC block 2017 of the non-legacy header field 2007, but no GI 2023a is added to the end of the final SC blocks 2019 and 2020 of thenon-legacy header fields 2011 and 2013.

FIG. 21 is a diagram illustrating an example of a detailed configurationof an SC block in a non-legacy header field according to the firstembodiment of the present disclosure. Illustrated in FIG. 21 are asymbol count N_(GI) of a GI when using the standard channel bandwidth, asymbol count N_(NLH) of non-legacy header per SC block when using thestandard channel bandwidth, GI period T_(GI), non-legacy header periodT_(NLH), and ratio of standard channel bandwidth and variable channelbandwidth (i.e., variable channel bandwidth/standard channel bandwidth)R_(CB).

Accordingly, R_(CB)=1 is equivalent to the SC block configuration of thenon-legacy header field 2007 in FIG. 20, while R_(CB)=2 is equivalent tothe SC block configuration of the non-legacy header fields 2011 and 2013in FIG. 20. R_(CB)=4 includes the non-legacy header 2100, duplicatednon-legacy header 2101, duplicated non-legacy header 2102, andduplicated non-legacy header 2103.

It is demanded in FIG. 21 to maintain the GI period to T_(GI) regardlessof the R_(CB), and keep the ratio between the GI period T_(GI) and thenon-legacy header period constant with regard to the non-legacy headerfield as well, in order to maintain interference avoidance capabilitiesregarding multipath delay waves and transmission efficiency, in the sameway as in FIG. 12. However, unlike the case of a data field, the bitcount of a non-legacy header is fixed, so increasing the symbol count inproportion to the R_(CB) is difficult. Accordingly, the non-legacyheader period T_(NLH) can be maintained constant by duplicating anR_(CB) count of non-legacy headers and disposing these in a single SCblock. The configuration of the GI is the same as that illustrated inFIG. 12. Thus, the ratio between the GI period and non-legacy headerperiod in an SC block of a non-legacy header field (i.e.,T_(GI)/T_(NLH)) is maintained constant.

FIG. 22 is a diagram illustrating an example of the configuration of anMF SC A-PPDU transmission device 2200 according to the first embodimentof the present disclosure. The transmission device 2200 has a basebandsignal processing unit 2201, a DAC 2202, an RF frontend 2203, and anantenna 2204. The baseband signal processing unit 2201 further includesa scrambler 2205, an LDPC encoder 2206, a modulator 2207, a duplicatingunit 2208, a symbol blocking unit 2209, and a GI insertion unit 2210.The transmission device 2200 has the same configuration as thetransmission device 300 except for the duplicating unit 2208, symbolblocking unit 2209, and GI insertion unit 2210, so description will beomitted.

The configuration in FIG. 23, for example, may be used when theduplicating unit 2208 duplicates the non-legacy header 2100. FIG. 23includes delays 2301, compositors 2302, and a selector 2303, and canhandle up to R_(CB)=4. As illustrated in FIG. 21, an (R_(CB)−1) count ofnon-legacy headers is duplicated in the SC block, and linked with a timedifference of N_(NLH) symbols, so the duplicating unit 2208 generatesthree duplicated non-legacy headers 2101, 2102, and 2103 with delays of1×N_(NLH) symbols, 2×N_(NLH) symbols, and 3×N_(NLH) symbols, as to thenon-legacy header 2100, and the non-legacy header 2100 that has beenprovided as input signals is composited with the duplicated non-legacyheaders 2101, 2102, and 2103.

The selector 2303 allows composited signals to pass, in accordance withthe input R_(CB). For example, if R_(CB)=2, the selector 2303 selectsinput signals of port 2. Signals of port 2 are the composited symbols ofthe non-legacy header 2100 and the duplicated non-legacy header 2101delayed by N_(NLH) symbols, and accordingly is equivalent to theconfiguration of R_(CB)=2 in FIG. 21.

If R_(CB)=4, the selector 2303 selects input signals of port 4. Signalsof port 4 are the composited symbols of the non-legacy header 2100, theduplicated non-legacy header 2101 delayed by 1×N_(NLH) symbols, theduplicated non-legacy header 2102 delayed by 2×N_(NLH) symbols, and theduplicated non-legacy header 2103 delayed by 3×N_(NLH) symbols, andaccordingly is equivalent to the configuration of R_(CB)=4 in FIG. 21.

The symbol blocking unit 2209 generates symbol blocks in increments ofan R_(CB)×N_(NLH) count with regard to the non-legacy header fields2007, 2011, and 2013, and generates symbol blocks in increments of anR_(CB)×N_(D) count with regard to the data fields 2010, 2012, and 2014.The GI insertion unit 2210 adds a GI of R_(CB)×N_(GI) symbols to thestart of the symbol block, thereby generating an SC block. Note that theorder of the modulator 2207 and the duplicating unit 2208 may bereversed.

According to the present first embodiment, the non-legacy header fields2011 and 2013 and the data fields 2010, 2012, and 2014 are transmittedby the same channel bandwidth, with the exception of the non-legacyheader field 2007 of the MF SC PPDU 2001 disposed at the start, soadding of the GI 2022 a to the end of the final SC blocks 2019 and 2020of the non-legacy header fields 2011 and 2013 can be omitted, and alsoadding of the GI 2023 a to the end of the final SC blocks 2018 and 2024of the data fields 2010 and 2012 can be omitted with the exception ofthe data field 2014 of the MF SC PPDU 2003 disposed at the end, Notethat the GI 2023 a may be added to the ends of the data fields 2010,2012, and 2014.

Accordingly, transmission efficiency can be improved as compared to theMF SC A-PPDU 1400 illustrated in FIG. 14. Also, sampling rate conversionprocessing becomes unnecessary at the boundary between the data field2010 and non-legacy header field 2011, at the boundary between thenon-legacy header field 2011 and the data field 2012, at the boundarybetween the data field 2012 and the non-legacy header field 2013, and atthe boundary between the non-legacy header field 2013 and the data field2014, so consumption of electric power can be reduced.

Second Embodiment

FIG. 24 is a diagram illustrating an example of the format of an MF ODMA-PPDU 2400 transmitted at the standard channel bandwidth, according toa second embodiment of the present disclosure. The MF OFDM A-PPDU 2400is made up of three MF OFDM PPDUs 2401, 2402, and 2403. The MF OFDMPPDUs are linked without an IFS or preamble therebetween, and includenon-legacy header fields and data fields.

For example, the MF OFDM PPDU 2401 disposed at the start of the MF OFDMA-PPDU 2400 includes a non-legacy header field 2407, data field 2410,legacy STF 2404, legacy CEF 2405, legacy header field 2406, non-legacySTF 2408, and non-legacy CEF 2409. Note that in a case where the datafields 2410, 2412, and 2414 are transmitted using SISO, the non-legacySTF 2408 and non-legacy CEF 2409 may be omitted, since the AGC leveladjusted at the legacy STF 2404 and channel estimation results obtainedat the legacy CEF 2405 can be used in the data fields 2410, 2412, and2414.

The MF OFDM PPDU 2403 disposed at the end of the MF OFDM A-PPDU 2400includes a non-legacy header field 2413, a data field 2414, an optionalAGC subfield 2415, and an optional TRN-R/T subfield 2416. Definitions ofthe legacy STF 2404, legacy CEF 2405, legacy header field 2406, legacyheader field 2406, non-legacy STF 2408, AGC subfield 2415, and TRN-R/Tsubfield 2416, of the MF OFDM A-PPDU 2400, are the same as thedefinitions of the corresponding fields of the MF OFDM PPDU 1800 in FIG.18, so description will be omitted.

The difference between the MF OFDM A-PPDU 1800 in FIG. 18 and the MFOFDM A-PPDU 2400 in FIG. 24 will be described below. In FIG. 24, thenon-legacy header field 2407 of the MF OFDM PPDU 2401 disposed at thestart is transmitted by SC modulation, but the non-legacy header fields2411 and 2413 of the MF OFDM PPDU 2402 and 2403 disposed at the secondsequential order and thereafter are transmitted by OFDM modulation.

Accordingly, a GI 2420 a is added to the end of the final SC block 2417of the non-legacy header field 2407, but adding the GI 2420 a to theends of the final OFDM symbols 2418 and 2419 of the non-legacy headerfields 2411 and 2413 can be omitted. Also, sampling rate conversionprocessing can be omitted at the boundary between the data field 2410and non-legacy header field 2411, between the non-legacy header field2411 and the data field 2412, between the data field 2412 and thenon-legacy header field 2413, and at the boundary between the non-legacyheader field 2413 and the data field 2414.

FIG. 25 is a diagram illustrating an example of the format of an MF OFDMA-PPDU 2500 transmitted at the variable channel bandwidth that is doublethe standard channel bandwidth, according to the second embodiment ofthe present disclosure. The MF OFDM A-PPDU 2500 is made up of three MFOFDM PPDUs 2501, 2502, and 2503. The MF OFDM PPDUs are linked without anIFS or preamble therebetween, and include non-legacy header fields anddata fields. For example, the MF OFDM PPDU 2501 disposed at the start ofthe MF OFDM A-PPDU 2500 includes a non-legacy header field 2507, datafield 2510, legacy STF 2504, legacy CEF 2505, legacy header field 2506,non-legacy STF 2508, and non-legacy CEF 2509.

The MF OFDM PPDU 2503 disposed at the end of the MF OFDM A-PPDU 2500includes a non-legacy header field 2513, a data field 2514, an optionalAGC subfield 2515, and an optional TRN-R/T subfield 2516, Definitions ofthe legacy STF 2504, legacy CEF 2505, legacy header field 2506,non-legacy STF 2508, non-legacy CEF 2509, data fields 2510, 2512, and2514, AGC subfield 2515, and TRN-R/T subfield 2516 are the same as thedefinitions of the corresponding fields of the MF OFDM PPDU 1900 in FIG.19, so description will be omitted.

The difference between the MF OFDM A-PPDU 1900 in FIG. 19 and the MFOFDM A-PPDU 2500 in FIG. 25 will be described below. In FIG. 25, thenon-legacy header field 2507 of the MF OFDM PPDU 2501 disposed at thestart is transmitted by SC modulation using the standard channelbandwidth, while the non-legacy header fields 2511 and 2513 of the MFOFDM PPDUs 2502 and 2503 disposed at the second sequential order andthereafter are transmitted by OFDM modulation using the variable channelbandwidth 2 B that is double the standard channel bandwidth B.

That is to say, as illustrated in FIG. 25, the non-legacy header field2507 is duplicated, and each is transmitted by SC modulation using thestandard channel bandwidth B (i.e., 2.16 GHz), each with a frequencyoffset B/2 that is half band of the standard channel bandwidth B (i.e.,1.08 GHz), but the non-legacy header fields 2511 and 2513 aretransmitted by OFDM modulation using the variable channel bandwidth 2 Bthat is a band double the standard channel bandwidth B (i.e., 4.32 GHz),

Accordingly, a GI 2520 a is added to the end of the final SC block 2517of the non-legacy header field 2507, but adding the GI 2520 a to the endof the final OFDM symbols 2518 and 2519 of the non-legacy header fields2511 and 2513 can be omitted. Also, sampling rate conversion processingcan be omitted at the boundary between the data field 2510 andnon-legacy header field 2511, between the non-legacy header field 2511and the data field 2512, between the data field 2512 and the non-legacyheader field 2513, and at the boundary between the non-legacy headerfield 2513 and the data field 2514.

FIG. 26 is a diagram illustrating an example of subcarrier mapping atthe non-legacy header fields 2711 and 2713 according to the secondembodiment of the present disclosure. Illustrated in FIG. 26 arestandard channel bandwidth B, a data subcarrier count N_(SNLH) (symbolcount of non-legacy header) when using the standard channel bandwidth B,and ratio of standard channel bandwidth and variable channel bandwidth(i.e., variable channel bandwidth/standard channel bandwidth) R_(CB).

Although data subcarriers are illustrated in FIG. 26 for the sake ofsimplicity, DC subcarrier, pilot subcarrier, and guard band are alsopresent in an actual MF OFDM PPDU. In FIG. 26, the data subcarrier countincreases proportionately to R_(CB) in the MF OFDM PPDU, so the symbolcount of non-legacy headers to be mapped to data subcarriers alsoincreases proportionately to R_(CB). However, unlike the case of a datafield, the bit count of a non-legacy header is fixed, so increasing thesymbol count of a non-legacy header in proportion to the R_(CB) isdifficult. Accordingly, an R_(CB) count of non-legacy headers isduplicated, and mapped to an RC_(B)×N_(SNLH) count of data subcarriers.

FIG. 27 is a diagram illustrating an example of the configuration of anMF OFDM A-PPDU transmission device 2700 according to the secondembodiment of the present disclosure. The transmission device 2700 has abaseband signal processing unit 2701, a DAC 2702, an RF frontend 2703,and an antenna 2704. The baseband signal processing unit 2701 furtherincludes a scrambler 2705, an LDPC encoder 2706, a modulator 2707, aduplicating unit 2708, a subcarrier mapping unit 2709, an IFFT unit2710, and a GI insertion unit 2711.

The transmission device 2700 has the same configuration as thetransmission device 700 except for the duplicating unit 2708, subcarriermapping unit 2709, IFFT unit 2710, and GI insertion unit 2711, sodescription will be omitted. The duplicating unit 2708 duplicates anR_(CB) count of the non-legacy header. The subcarrier mapping unit 2709maps non-legacy header 2521 in increments of an R_(CB)×N_(SNLH) count todata subcarriers with regard to the non-legacy header fields 2511 and2513, and maps payload data 2522 in increments of an R_(CB)×N_(D) countto data subcarriers with regard to data fields 2510, 2512, and 2514. TheIFFT unit 2710 converts the non-legacy header 2521 or payload data 2522subjected to subcarrier mapping at the frequency region into time regionsignals by IFFT processing of R_(CB)×512 points. The GI insertion unit2010 copies the last R_(CB)×N_(GI) samples of the output signals fromthe IFFT unit 2710 (GI 2523), and connects to the start of IFFT outputsignals, thereby generating OFDM symbols. Note that the order of themodulator 2707 and the duplicating unit 2708 may be reversed.

According to the present second embodiment, the non-legacy header fieldsand the data fields are transmitted by the same channel bandwidth usingOFDM modulation, with the exception of the MF OFDM PPDU disposed at thestart, so adding of a GI 2523 to the end of the non-legacy header field2521 can be omitted, and rate conversion processing at the boundarybetween the non-legacy header field and data field becomes unnecessary,so consumption of electric power can be reduced.

Third Embodiment

In NG60 WiGig, the GI period of the SC block in the data field of an MFSC PPDU, or the GI period of OFDM symbols in the data field of an MFOFDM PPDU, can be changed to short, normal, or long, by changing thesettings of the GI Length field in the non-legacy header illustrated inFIG. 10. In a third embodiment of the present disclosure, a method forgenerating an SC block for a non-legacy header field in a case ofchanging the GI period will be described with regard to the MF SC A-PPDU2000 according to the first embodiment, illustrated in FIG. 20.

In the present embodiment, when changing the GI period in the MF SCA-PPDU 2000, the GI Length of the non-legacy header field 2007 of the MFSC PPDU 2001 disposed at the start is set to a desired value. Changingof the GI Length is applied to the data field in a conventional MF SCPPDU, but in the third embodiment of the present disclosure, this isalso applied to all fields from the data field 2010 of the MF SC PPDU2001 disposed at the start of the MF SC A-PPDU 2000 and thereafter. Thatis to say, the change of the GI period is also applied to the non-legacyheader fields (2011, 2013) of the MF SC PPDUs (2002, 2003) disposed atthe second sequential order and thereafter.

Accordingly, The GI Length fields of the non-legacy header fields 2011and 2013 of the MF SC PPDUs 2002 and 2003 disposed at the secondsequential order and thereafter are set to the same value as the GILength field of the non-legacy header field 2007 of the MF SC PPDU 2001disposed at the start. Note that the GI period of non-legacy headerfield 2007 of the MF SC PPDU 2001 disposed at the start is normalregardless of the settings of the GI Length field, and is unchanged.

A method of generating an SC block of a non-legacy header field in an MFSC PPDU disposed at the second sequential order and thereafter in a casewhere the GI period has been changed to a short GI will be describedbelow with reference to FIG. 28. An example will be described here wherethe size of the non-legacy header is 64 bits, in a case wheretransmission is performed at the variable channel bandwidth of R_(CB)=2.Also, the symbol count of a short GI is a count that is N_(S) symbolsless than a normal GI.

(Step S2801) A 64-bit non-legacy header is scrambled, and 64 bits ofscrambler output signals are obtained.

(Step S2802) 440 (i.e., 504−64) bits of 0s are added to the end of the64 bits of scrambler output signals, and an LDPC codeword that has acodelength of 672 bits is obtained by 3/4 code rate LDPC encoding.

(Step S2803) The 440−N_(S)/R_(CB) bits of bits 65 through 504, and theeight bits of bits 665 through 672, are deleted from the LDPC codeword,thereby obtaining a first bit sequence of 224+N_(S)/R_(CB).

(Step S2804) The 440−N_(S)/R_(CB) bits of bits 65 through 504, and theeight bits of bits 657 through 664, are deleted from the LDPC codeword,thereby obtaining a reserve bit sequence of 224+N_(S)/R_(CB). Further,the XOR is computed for a PN (Pseudo random Noise) sequence obtained byinitializing the shift register of the scrambler used in step S2801 toall 1s and the reserve bit sequence, thereby obtaining a second bitsequence of 224+N_(S)/R_(CB).

(Step S2805) The first bit sequence and the second bit sequence arelinked, thereby obtaining a third bit sequence of 448+N_(S).

(Step S2806) An R_(CB) count of third bit sequence are linked, therebyobtaining a fourth bit sequence of R_(CB)×(448+N_(s)) bits.

(Step S2807) The fourth bit sequence is subjected to π/2-BPSKmodulation, thereby obtaining a symbol block of R_(CB)×(448+N_(s))symbols.

(Step S2808) A GI of R_(CB)×(N_(GI)−N_(S)) symbols is added to the startof the symbol block, thereby obtaining an SC block ofR_(CB)×(N_(GI)+448) symbols. Note that the order of step S2807 and stepS2808 may be reversed.

Note that in a case of changing a GI period to a long GI, the N_(S) instep S2801 through step S2808 should be read as −N_(L), since a long GIhas N_(L) more symbols than a normal GI.

According to the third embodiment of the present disclosure, the GIperiod and non-legacy header period in the SC block can be changed inaccordance with the settings of the GI Length field settings of thenon-legacy header, so transmission path situations can be flexiblyhandled.

Various forms of embodiments according to the present disclosure includethe following.

A transmission device according to a first disclosure includes: a signalprocessing circuit that generates an aggregate physical layerconvergence protocol data unit (A-PPDU) by adding a guard interval toeach of a first part of a first physical layer convergence protocol dataunit (PPDU) transmitted over each of a first through L'th channel of apredetermined channel bandwidth, where L is an integer of 2 or greater,a second part of the first PPDU transmitted over each of an (L+1)'ththrough P'th channel, which is a variable channel bandwidth that is Ntimes the predetermined channel bandwidth, where N is an integer of 2 orgreater and P is an integer of L+1 or greater, and a second PPDUtransmitted over the (L+1)'th through P'th channel; and a wirelesscircuit that transmits the A-PPDU. The first PPDU includes a legacy STF,a legacy CEF, a legacy header field, a non-legacy STF, a non-legacy CEF,one or more non-legacy header fields including one or more non-legacyheaders, and one or more data fields including one or more payload data.The first part of the first PPDU includes the legacy STF, the legacyCEF, the legacy header field, and the non-legacy header field. Thesecond part of the first PPDU includes the non-legacy STF, thenon-legacy CEF, and the one or more data fields. The second PPDUincludes the one or more non-legacy header fields and the one or moredata fields. In a case where the wireless circuit transmits the firstPPDU and the second PPDU by single carrier, each of the one or morenon-legacy header fields of the second PPDU includes a non-legacy headerthat has been repeated N times.

A transmission device according to a second disclosure is thetransmission device according to the first disclosure, wherein thesignal processing unit adds the guard interval of N_(GI) symbols (whereN_(GI) is an integer of 1 or greater) to the non-legacy header ofN_(NLH) symbols (where N_(NLH) is an integer of 1 or greater), includedin the one or more non-legacy header fields in the first part of thefirst PPDU, and adds the guard interval of (N_(GI)+M)×N symbols (where Mis an integer of 0 or greater) to the non-legacy header of N_(NLH)−Msymbols, and adds the guard interval of (N_(GI)−M)×N symbols to thenon-legacy header of N_(NLH)+M symbols, included in the non-legacyheader field in the second PPDU.

A transmission method according to a third disclosure includes:generating an aggregate physical layer convergence protocol data unit(A-PPDU) by adding a guard interval to each of a first part of a firstphysical layer convergence protocol data unit (PPDU) transmitted overeach of a first through L'th channel of a predetermined channelbandwidth, where L is an integer of 2 or greater, a second part of thefirst PPDU transmitted over each of an (L+1)'th through P'th channel,which is a variable channel bandwidth that is N times the predeterminedchannel bandwidth, and a second PPDU transmitted over the (L+1)'ththrough P'th channel; and transmitting the A-PPDU. The first PPDUincludes a legacy STF, a legacy CEF, a legacy header field, a non-legacySTF, a non-legacy CEF, one or more non-legacy header fields includingone or more non-legacy headers, and one or more data fields includingone or more payload data. The first part of the first PPDU includes thelegacy STF, the legacy CEF, the legacy header field, and the non-legacyheader field. The second part of the first PPDU includes the non-legacySTF, the non-legacy CEF, and the one or more data fields. The secondPPDU includes the one or more non-legacy header fields and the one ormore data fields. In a case of transmitting the first PPDU and thesecond PPDU by single carrier, each of the one or more non-legacy headerfields of the second PPDU includes a non-legacy header that has beenrepeated N times.

A transmission method according to a fourth aspect is the transmissiondevice according to the third aspect, wherein the guard interval ofN_(GI) symbols (where N_(GI) is an integer of 1 or greater) is added tothe non-legacy header of N_(NLH) symbols (where N_(NLH) is an integer of1 or greater), included in the one or more non-legacy header fields inthe first part of the first PPDU, and wherein the guard interval of(N_(GI)+M)×N symbols (where M is an integer of 0 or greater) is added tothe non-legacy header of N_(NLH)−M symbols, and the guard interval of(N_(GI)−M)×N symbols is added to the non-legacy header of N_(NLH)+Msymbols, included in the non-legacy header field in the second PPDU.

Although various embodiments have been described above with reference tothe drawings, it is needless to say that the present disclosure is notrestricted to these examples. It is clear that one skilled in the artwill be able to reach various alterations and modifications within thescope of the Claims, and such should be understood to belong to thetechnical scope of the present disclosure as a matter of course. Variouscomponents in the above-described embodiments may be optionally combinedwithout departing from the essence of the disclosure.

Although examples of configuring the present disclosure using hardwarehave been described in the above-described embodiments, the presentdisclosure may be realized by software in cooperation with hardware aswell.

The functional blocks used in the description of the above-describedembodiments typically are realized as large scale integration (LSI) thatis an integrated circuit having input terminals and output terminals.These may be individually formed into one chip, or part or all may beincluded in one chip. Also, while description has been made regarding anLSI, there are different names such as IC, system LSI, super LSI, andultra LSI, depending on the degree of integration.

The circuit integration technique is not restricted to LSIs, anddedicated circuits or general-purpose processors may be used to realizethe same. An field programmable gate array (FPGA) which can beprogrammed after manufacturing the LSI, or a reconfigurable processorwhere circuit cell connections and settings within the LSI can bereconfigured, may be used.

Further, in the event of the advent of an integrated circuit technologywhich would replace LSIs by advance of semiconductor technology or aseparate technology derived therefrom, such a technology may be used forintegration of the functional blocks, as a matter of course. Applicationof biotechnology, for example, is a possibility.

The present disclosure is applicable to a method of configuring andtransmitting A-PPDUs in a wireless communication system including acellular device, smartphone, tablet terminal, and television terminal,that transmits and receives moving images (video), still images(pictures) text data, audio data, and control data.

What is claimed is:
 1. A transmission device, comprising: a signalprocessing circuit that generates an aggregate physical layerconvergence protocol data unit (A-PPDU) by adding a guard interval toeach of a first part of a first physical layer convergence protocol dataunit (PPDU) transmitted over each of a first through L'th channel of apredetermined channel bandwidth, where L is an integer of 2 or greater,a second part of the first PPDU transmitted over each of an (L+1)'ththrough P'th channel, which is a variable channel bandwidth that is Ntimes the predetermined channel bandwidth, where N is an integer of 1 orgreater and P is an integer of L+1 or greater, and a second PPDUtransmitted over the (L+1)'th through P'th channel; and a wirelesscircuit that transmits the A-PPDU, wherein the first PPDU includes alegacy STF, a legacy CEF, a legacy header field, a non-legacy STF, anon-legacy CEF, one or more non-legacy header fields including one ormore non-legacy headers, and one or more data fields including one ormore payload data, wherein the first part of the first PPDU includes thelegacy STF, the legacy CEF, the legacy header field, and the non-legacyheader field, wherein the second part of the first PPDU includes thenon-legacy STF, the non-legacy CEF, and the one or more data fields,wherein the second PPDU includes the one or more non-legacy headerfields and the one or more data fields, and wherein, in a case where thewireless circuit transmits the first PPDU and the second PPDU by singlecarrier, each of the one or more non-legacy header fields of the secondPPDU includes a non-legacy header that has been repeated N times.
 2. Thetransmission device according to claim 1, wherein the signal processingunit adds the guard interval of N_(GI) symbols (where N_(GI) is aninteger of 1 or greater) to the non-legacy header of N_(NLH) symbols(where N_(NLH) is an integer of 1 or greater), included in the one ormore non-legacy header fields in the first part of the first PPDU, andadds the guard interval of (N_(GI)+M)×N symbols (where M is an integerof 0 or greater) to the non-legacy header of N_(NLH)−M symbols, and addsthe guard interval of (N_(GI)−M)×N symbols to the non-legacy header ofN_(NLH)+M symbols, included in the non-legacy header field in the secondPPDU.
 3. A transmission method, comprising: generating an aggregatephysical layer convergence protocol data unit (A-PPDU by adding a guardinterval to each of a first part of a first physical layer convergenceprotocol data unit (PPDU) transmitted over each of a first through L'thchannel of a predetermined channel bandwidth, where L is an integer of 2or greater, a second part of the first PPDU transmitted over each of an(L+1)'th through P'th channel, which is a variable channel bandwidththat is N times the predetermined channel bandwidth, and a second PPDUtransmitted over the (L+1)'th through P'th channel; and transmitting theA-PPDU, wherein the first PPDU includes a legacy STF, a legacy CEF, alegacy header field, a non-legacy STF, a non-legacy CEF, one or morenon-legacy header fields including one or more non-legacy headers, andone or more data fields including one or more payload data, wherein thefirst part of the first PPDU includes the legacy STF, the legacy CEF,the legacy header field, and the non-legacy header field, wherein thesecond part of the first PPDU includes the non-legacy STF, thenon-legacy CEF, and the one or more data fields, wherein the second PPDUincludes the one or more non-legacy header fields and the one or moredata fields, and wherein, in a case of transmitting the first PPDU andthe second PPDU by single carrier, each of the one or more non-legacyheader fields of the second PPDU includes a non-legacy header that hasbeen repeated N times.
 4. The transmission method according to claim 3,wherein the guard interval of N_(GI) symbols (where N_(GI) is an integerof 1 or greater) is added to the non-legacy header of N_(NLH) symbols(where N_(NLH) is an integer of 1 or greater), included in the one ormore non-legacy header fields in the first part of the first PPDU, andwherein the guard interval of (N_(GI)+M)×N symbols (where M is aninteger of 0 or greater) is added to the non-legacy header of N_(NLH)−Msymbols, and the guard interval of (N_(GI)−M)×N symbols is added to thenon-legacy header of N_(NLH)+M symbols, included in the non-legacyheader field in the second PPDU.